This invention relates to scanners, in particular to the optical system of a scanner.
A traditional optical system for a scanner is shown in FIG. 1. The optical system comprises a series of reflecting mirrors, a first reflecting mirror 111, a second reflecting mirror 112 and a third reflecting mirror 113. These three mirrors reflect light back and forth horizontally. The light reflected from the third mirror passes through a lens 12 and is incident on an image sensor 13. Such an optical system with reflected light traversing in a horizontal direction occupies a great deal of space, and makes the scanner bulky.